Evaluation of the biomass production, energy yield and nutrient removal of Eucalyptus dunnii Maiden grown in short rotation coppice under two initial planting densities and harvest systems

Abstract

Bioenergy is an important component of the renewable energy mix, helping to ensure a stable energy supply. One of the alternatives for bioenergy production is the use of Eucalypts sp. grown on short rotation coppice under different harvest systems. Because in some cases all components of the tree are harvested, there could be implications regarding the sustainability of this type of system. For this reason, new information is required to assess this alternative energy source. The objective of the research was to estimate the biomass production, energy yield, nutrient concentration, nutrient removal, and energy yield per kg of nutrient removal (EYNR) of four years old E. dunnii using two initial planting densities (3 m × 1.5 m and 3 m × 0.75 m) into two different sites comparing two harvest systems; stemwood without debarking (System A) vs whole tree (System B).There was no impact of the planting density on the biomass production and energy yield per hectare. Significant differences of nutrient concentrations in different tree components were observed, but generally with similar magnitude between the two densities. The magnitude of nutrients removal caused by forest biomass varied depending on the nutrient, tree component, and biomass production. For the biomass production, energy yield, nutrient removal per hectare and EYNR system B was always significantly higher than system A. According to these results system B is more efficient from the energy yield perspective, but less sustainable from the soil fertility point of view.